The effects of modified ignition timing on cold start HC emissions and WOT performance of an LPG fuelled SI engine with thermal barrier layer coated piston

Abstract

In this study, the effect of modified ignition timing of an LPG fuelled spark ignition engine on cold start Hydrocarbon emission (HC) at the wide open throttle (WOT) conditions performance and emission characteristics were investigated when using a thermal barrier layer (TBL) coated piston. The engine was tested at the variable ignition timing. At the first stage cold start HC emission was measured for the first 180 s. Secondly, the performance and HC emissions were measured at the WOT condition. Cold start HC emission in the TBL piston has been decreased considerable. In the case of using TBL piston and variable ignition timing, at the high engine speed the engine torque and brake power have been increased as 15% at the 2700 rpm. Specific fuel consumption (SFC) was decreased at the variable ignition timing expect for 1500 and 1800 rev min-1. Maximum reduction was observed by 8.5% at the 2700 rpm. Key words: Hydrocarbon emissions, cold start, thermal barrier layer, liquefied petroleum gas.